1. Field of the Invention
The present invention relates to steerable drive axles, for aircraft loaders or the like, capable of large cramp angles; and more particularly relates to such an axle which utilizes first sets of bearing surfaces for correcting pivot axis misalignment and second sets of bearing surfaces for allowing low stress pivotable movement about the resulting pivot axis.
2. Description of the Prior Art
Vehicles such as aircraft loaders or the like having steerable drive axles are well known in the art. One such aircraft loader is disclosed in assignee's U.S. Guyaux Pat. No. 3,666,127 which issued on May 30, 1972. The Guyaux type loader is capable of providing only about a 30.degree. cramp angle, and the loader must be maneuvered into substantially aligned abutting engagement with an aircraft cargo door or the like. Many times the available area in which the loader is being maneuvered is quite small and therefore a small turning radius, or large cramp angle, is very desirable.
The problem of providing a small radius of turn was solved in some vehicles by providing the vehicle with a single centrally disposed driven wheel at the front of the vehicle and a pair of rear nondriven wheels. However, this type of three wheeled vehicle has the disadvantage of being unstable. Also, placement of a wheel centrally in front of the vehicle makes the accessability to the wheel for maintenance difficult, and also takes up a large amount of space which otherwise could be used for fuel tanks or the like.
It has been determined that an increase in the cramp angle, which decreases the radius of turn of the vehicle, makes it more difficult to maintain exact axial alignment of the top and bottom king pins during the turns. This misalignment, unless corrected, provides additional wear of the trunnion assembly bearings thereby reducing the life of the bearings.